Calcium influx during striatal upstates (Evans et al. 2013)

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Accession:150912
"... To investigate the mechanisms that underlie the relationship between calcium and AP timing, we have developed a realistic biophysical model of a medium spiny neuron (MSN). ... Using this model, we found that either the slow inactivation of dendritic sodium channels (NaSI) or the calcium inactivation of voltage-gated calcium channels (CDI) can cause high calcium corresponding to early APs and lower calcium corresponding to later APs. We found that only CDI can account for the experimental observation that sensitivity to AP timing is dependent on NMDA receptors. Additional simulations demonstrated a mechanism by which MSNs can dynamically modulate their sensitivity to AP timing and show that sensitivity to specifically timed pre- and postsynaptic pairings (as in spike timing-dependent plasticity protocols) is altered by the timing of the pairing within the upstate. …"
Reference:
1 . Evans RC, Maniar YM, Blackwell KT (2013) Dynamic modulation of spike timing-dependent calcium influx during corticostriatal upstates. J Neurophysiol 110:1631-45 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell;
Brain Region(s)/Organism: Striatum;
Cell Type(s): Neostriatum medium spiny direct pathway GABA cell;
Channel(s): I Na,t; I L high threshold; I N; I A; I K; I K,Ca; I A, slow; I Krp; I R;
Gap Junctions:
Receptor(s): AMPA; NMDA; Gaba;
Gene(s): Cav1.3 CACNA1D; Cav1.2 CACNA1C; Cav2.2 CACNA1B;
Transmitter(s):
Simulation Environment: GENESIS;
Model Concept(s): Oscillations; STDP; Calcium dynamics;
Implementer(s): Evans, Rebekah [Rebekah.Evans at nih.gov];
Search NeuronDB for information about:  Neostriatum medium spiny direct pathway GABA cell; AMPA; NMDA; Gaba; I Na,t; I L high threshold; I N; I A; I K; I K,Ca; I A, slow; I Krp; I R; 
 //function to add calcium channels to spines 

function addCaChannelspines(channelName, compPath, conductance, caBufferName)
  str channelName, compPath
  float conductance
  str caBufferName

  pushe {compPath}

    // Copy the channel from library
    copy /library/{channelName} {channelName}
    copy /library/{channelName}GHK {channelName}GHK

    // Set the new conductance
    float len = {getfield {compPath} len}
    float dia = {getfield {compPath} dia}
    float pi = 3.141592653589793
    float surf = {len*dia*pi} 

    // echo "Channel: "{channelName}", conductance "{conductance}"S/m²"
    // echo "Compartment: "{compPath}", surface area "{surf}"m²"
    setfield {channelName} Gbar {conductance*surf}

 	coupleCaBufferCaChannel {caBufferName} {compPath} {channelName}


    // Couple channel, its GHK object and compartment together
    addmsg {compPath} {channelName}GHK VOLTAGE Vm
    addmsg {compPath} {channelName} VOLTAGE Vm
    addmsg {channelName}GHK {compPath} CHANNEL Gk Ek
    addmsg {channelName} {channelName}GHK PERMEABILITY Gk

//     float len = {getfield {compPath} len}
//     float dia = {getfield {compPath} dia}
//     float pi = 3.141592653589793
//     float surf = {len*dia*pi}

//     // echo "conductance (unscaled): "{conductance}
//     // echo "Compartment: "{compPath}" surface area "{surf}"m²"
//     setfield {channelName} Gbar {conductance*surf}

  pope

end

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